The present invention relates to a pushbutton switch of a low profile capable of producing a click when a switch device is actuated in response to depression of a switch stem.
There has been proposed a pushbutton switch having a thin switch device disposed vertically on a side of a casing and a stem disposed for vertical movement into and out of the casing for actuating the switch device. Such thin switch devices limit obtainable profile reductions which may be obtained in pushbutton switches, and it has been difficult to make the pushbutton switch thinner in configuration.
According to another proposal, a thin switch device is disposed horizontally on the bottom of a casing, and a stem arranged for vertical movement into and out of the casing is biased by a spring which projects outwardly from the casing. In such a pushbutton switch, the switch device can be actuated by being pushed by the stem when the stem is displaced against the switch device by the force of the spring.
The pushbutton switch of this type is of a low profile since the thin switch device is positioned horizontally on the bottom of the casing. With the low profile shape, however, the switch device is subjected to bouncing due to strong depression of the stem, which causes chattering, with the result that it takes a relatively long period of time for a current flowing through the switch device to reach a predetermined level, and pulsed currents tend to flow several times until the current reaches the predetermined level. It is desirable that such a chattering phenomenon be eliminated as it could adversely affect an electric circuit in which the pushbutton switch is incorporated.
It is also desirable that the pushbutton switch be of a low profile and also be capable of producing a definite click upon operation of the switch device to allow the operator to confirm the operation of the switch device in order to avoid malfunctioning thereof.